1. Field of the Invention
The present invention relates to systems and methods for disseminating data, and in particular to a system and method for transmitting program content via alternative or backup networks.
2. Description of the Related Art
The dissemination of media programs such as television broadcasts and movies in digital form has become commonplace. Such dissemination typically involves a first transmission from a content provider (e.g. ESPN, NBC, HBO) that generates or otherwise obtains the media program, to a service provider (e.g. DIRECTV, DISH, TIME WARNER CABLE), and a second transmission of the media program from the service provider to subscribers or other customers for reception and viewing.
Digitized media programs are quite large, often gigabits in size. Hence, digitized media programs are typically compressed to reduce their size and bit rate to values supportable by the communications system over which the media program is transmitted. This is the case for both the first transmission from the content provider to the service provider, and for transmission from the service provider to the customer.
The encoders performing such compression can be set to provide encoded media programs of selectable frame rates and resolutions, with higher resolution and frame rate media programs requiring greater bandwidth for transmission. Because the quality of the media program ultimately received by the subscriber can be no better than the quality of the media program transmitted from the content provider to the service provider, the media programs are increasingly transmitted via high bandwidth terrestrial/fiber communications systems. This permits delivery of media programs of high resolution and frame rate. The service provider may then decode and re-encode the delivered media programs to a frame resolution and frame rate that are suitable for the communication link to the subscriber and the desired image quality.
In many cases (for example, with live feeds), the media program is transmitted from the content provider to the service provider and the subscribers more or less in real time (e.g. with perhaps a short delay for processing and to permit inappropriate subject matter to be excised before transmission). In such circumstances at least, even occasional temporary outages in the communication link between the content provider and the service provider are unacceptable. Accordingly, backup communication links are used to allow service providers to obtain the program content via other means. However, such backup communication links are of little value if the service provider cannot accurately and rapidly associate the program content obtained via the backup communications link with the program content that was lost via the primary communication link.
What is needed is a system and method for reliably and unambiguously transmitting data that can be used to associate program content from primary and back up communication links and sources. The system and method transmitting this information should preferably not require any change in existing transmission protocols, nor require significant increases in the required bandwidth of the primary and/or backup communications links. The system and method should also preferably piggyback on transmissions that themselves implicate the need to use the backup program content, so that the proper functioning of one transmission assures that the proper program content is chosen for backup. This disclosure presents a system and method that satisfies this need.